2nd Gen Non-Engine/Transmission What is the best oil for rear axle

[98 ram fan]

Hi everyone
Wanting to change the gear oil in my 98 2500 4.10 rearend with limited slip. Bought the truck a little over 6 months ago and its time to do that part of the maintenance. As far as I know this may be the original gear oil from 1998, (the tires were not changed since 2000 so you tell me..). I need to know a good rear end lubrication and if I need to use a limited slip additive.
I also am looking for a good transmission shop in southern california (Riverside/Orange county) to beef up the transmission for more power for towing.

 

[JR]

Any 75w90 will be just fine. Your service manual calls for 80w90 but 75w90 is synthetic, slightly thinner at cold temps and will not shear out and break down as quickly as 80w90 under load and high temps. You will also need limited slip additive.

I would strongly consider doing the front diff also if this is a 4x4 truck. I generally stick with 80w90 in the front diff, the front just rides around disengaged most of the time and does not see the stresses or loads the rear does from towing. 80w90 is alot cheaper than 75w90.

 

[NIsaacs]

If you are going to add power and tow, I would use 85/140 in the rear. That's what I use in all my Cummins powered trucks, they are all modified and tow heavy. I just use a store brand, such as Napa or CARQUEST, made by Valvoline.

Nick

 

[Bob4x4]

With the dana 70 and 80 series 75/140 has always been the recommended fill for towing/heavy duty use.My Dana 80 never had any issues for 1/4 million miles with more than the normal duty cycle,drag racing,sled pulling ,trailer towing and many miles of off roading.A Mag-hytech cover and the mopar 75/140 fluid for most of the miles than an AFE cover with a Mobil 1 fill when used for a test fit

 

[DavidC]

Mine has Royal Purple and no additive needed for Chatter.

Dave

 

[GAmes]

I use RP also. The differential is the only part of my drivetrain that is original.

 

[NIsaacs]

I use RP also. The differential is the only part of my drivetrain that is original.

That's awesome!

Nick

 

[JR]

I use RP also. The differential is the only part of my drivetrain that is original.

In what grade?

I don't push a ton of power nor do I tow all the time (realistically, 40% of my miles are tow miles). That being said, 75w90 has worked well for me. My previous truck had 380k on the clock and the rear end was still original. I know that's not half of what you've accumulated, just curious what you use. I only put 110k of those miles on but know the original owner and it was used exclusively for towing while he owned it. I obtained all his service records and 75w90 was the listed fluid, it worked for him so I chose to use the same.

 

[wcjp]

I typically use Valvoline full synthetic 75w90.

 

[RustyJC]

I towed a very heavy 5th wheel with my 2002 3500 ETH/DEE with 4.10s. I used Royal Purple 85W/140 synthetic in the Dana 80 and never had any problems whatsoever. No friction modifier additive is necessary for the limited slip with the RP - like Prego, "it's in there".

Rusty

 

[GAmes]

In what grade?

Currently 75W140, but I have used different grades over the years, i.e. whatever the NAPA had in stock when I needed some. Now I buy it in bulk on line, usually from Amazon.

 

[Missouri Mule]

I run Amsoil Severe Gear 75w-140 front and back. I'm on the highway a lot running empty and with a load in the bed ( I don't use my utility trailer any more since I bought Moose (FL 60 Freightliner). Well for a few years when I made watermelon runs but not for 10 years now (utility trailer used to store plastic crates in it now). The 75w-140 is probably over kill put I wanted extra protection.

 

[98 ram fan]

Fairly close to what I did Nick. Went with Mobil 1 75w-140 and Mopar limited slip addative. Clicking in rear seems to have been almost eliminated when turning left or right. Thanks for your input.

Randy (98 ram fan)

 

[98 ram fan]

I really appreciate all the quick replys from everyone. Do to the general consensus of everyones experience I went with Mobil 1 in 75w-140 and mopar limited slip addative. My truck is still fairly new (75,000 miles) and is primarily used to pull my 8000 Lb. travel trailer so that is why I chose 75w-140. Thanks again guys for real world solutions.

Randy (98 ram fan)

98 ram 2500 5.9 12v 4.10 rear 2wd stock....... for now

 

[wlowe]

Royal purple in mine, front and rear, no additive. Originally used amsoil but Rp was easier to find.

 

[SSage]

I've been using Valvoline Syn Power 75w140 for years. Seems to work fine with the LS, the old 12 valve Dana 80 hasn't blown up yet. Use the same in the 2003.

http://www.walmart.com/ip/VALVOLINE-VV982-Gear-Oil-Full-Synthetic-32-Oz-75W-140/41102447?action=product_interest&action_type=title&item_id=41102447&placement_id=irs-2-m2&strategy=PWVAV&visitor_id&category=&client_guid=26634a0b-eb0c-4bcf-85a5-34bc4300cde1&customer_id_enc&config_id=2&parent_item_id=40936833&parent_anchor_item_id=40936833&guid=750934ec-429a-419c-820c-ad44b3922e24&bucket_id=irsbucketdefault&beacon_version=1.0.1&findingMethod=p13n

I get mine at Wal-Mart... YMMV

 

[Regcabguy]

75-90 Amsoil Severe Gear lube's in my AAM axle. It's still transparent after 60K. You may need to add friction modifer.

 

[JMcCoy]

I found I needed a little friction modifier with Mobil 1 75-90. If you are getting any clicking or chatter, put in a half tube and that should clear it up. I currently have 75-140 synthetic (forget the brand) and I easily gave up 1-1.5 mpg.

 

[fest3er]

A number of studies have shown that 75W-90 really isn't adequate for use behind the Cummins diesel.

The best lube for lightweight/unladen usage is Amsoil Severe Gear 75W-110.

The best lube for moderate to heavy towing and/or high power/torque operation is Amsoil Severe Gear 75W-140.

 

[GAmes]

What would the best synthetic be if you weren't an Amsoil advocate? 1.2 million on my D80 so far, never used Amsoil.